I have bred and made seeds from over 200 cultivars in my more than 40 years in the cannabis industry. The size of my seed collection has varied over the years. Some were lost during a law enforcement seizure when I was arrested for cannabis cultivation many years ago. Fortunately, many were saved or recreated.
Today, I have more than 100 unreleased cultivars in seed form. But, as a friend recently pointed out, I am getting old, and so is my seed collection. Most of my seeds are between 15 and 20 years old. The collection consists of many of the popular cultivars Trichome Technologies bred in the early 1990s (such as Purple Kush), dozens of hybrids, as well as multiple interesting crossbreeds that are the result of decades of breeding, as well as a few landrace cultivars.
Most importantly, many of these long-preserved varieties I possess are those that I and multiple old friends can no longer enjoy. The same friend who noted my age suggested that I attempt to reproduce the seeds I have and make them publicly available while there remains a small possibility they can germinate.
They were not stored in a freezer or a refrigerator with desiccants—a shoddy start. However, they were consistently stored in sealed containers in the same cool, dry location. I have many friends who have germinated seeds that were 30-plus years old and stored in similar conditions with no problems. But there are no guarantees.
The (Not-So) Basics of Cannabis Seed Germination
The state of my seed collection has made me wonder whether modern technological and knowledge advancements have led to a way to germinate seeds that increases the odds of successfully germinating old seeds. To answer this question, I interviewed multiple tissue culture technicians, old-school breeders, and botanical experts.
The consensus was to leverage the same method utilized for decades while adding touches of modern updates to slightly increase the chances of germinating older seeds.
All experts I spoke with agreed that it is impossible to germinate a nonviable seed. An easy way to test seeds for viability is to place them in a cup of distilled, pH-neutral water. The viable seeds will sink, while the nonviable ones will float. Give the floating seeds 24 hours to sink. The submerged seeds should germinate within 48 hours, after which they need to be placed into germination plugs or another media specifically formulated for seed germination.
Some experts suggested germinating seeds in test tubes and utilizing Agar, a natural gel that can be used in tissue propagation, as the media. In this method, growers can dictate the Agar’s specific nutrient and pH base to optimize germination—basically growing in vitro for sterility.
Embryo rescue is another tissue culture method that can assist in older seed germination. I first heard of this practice when I was 13 years old: It consists of removing the seed coat/testa from a live embryo that is too weak to shed it on its own. The seed coat, which normally acts as a protective barrier for the seed, can act as a hindrance to germination by becoming too tough of a barrier for the embryo. By removing the testa from the live embryo, you increase the chances of healthy germination.
Boost the Odds
Some of the experts I interviewed suggested growers consider seed germination aids—solutions that can increase the odds of germination success. One such germination fluid is called a “Germinator solution” by Cannomic Laboratories. This product is advertised as a seed-sprouting solution.
Another product to consider is one from Grow Genius that contains 40% mono-silicic acid and is advertised as facilitating healthy germination.
Gibberellic acid (GA3) is a naturally occurring plant hormone that regulates plant growth and development. It can be applied directly to plants to encourage growth and ripening, and studies have shown it can be used as a soaking solution to achieve a higher germination rate and germination potential compared to those that had not been soaked. In fact, results showed that GA3 exposure increased seed germination rate by 14% to 27%.
The optimal concentration of GA3 utilized for seed soaking is 50 to 150 parts per million (PPM) in different plants, but it has been found that the optimal concentration for hemp seed is 400 milligrams/L to 600 milligrams/L.
While it is true that GA3 can aid the germination of old seeds, it is also true that the resulting sprouts sometimes stretch too much and die soon after germination. Typically, one would soak seeds in GA3 solution for up to 24 hours at the hemp seed-appropriate concentration. But given the propensity for stretching, perhaps I will skip using the GA3 until I can prevent any stretching of the resulting sprouts, yet it’s certainly worth further investigation.
How to Germinate Old Cannabis Seeds
With this in mind, here is how I would go about germinating my old seeds:
- Rinse the seeds utilizing a solution combining pH-adjusted distilled water with hydrogen peroxide in a 10:1 ratio for two minutes and dry them off with a paper towel.
- Submerge the seeds into pH-adjusted distilled water for up to 48 hours.
- Any seed that has germinated should be folded into a moist paper towel and placed into a sealed container until the seeds sprout (in two or three days).
- For seeds that do not germinate within 48 hours, remove the seed coat. After another 48 hours, any seeds that have not germinated should be considered nonviable and discarded.
- After the seeds sprout, they are placed into a growing medium (peat moss cubes, coco fiber cubes, foam type cubes, rockwool cubes) until the seedling sprouts established roots.
- When the seedling is fully formed and healthy roots are established and visible around and at the bottom of the cube, it is ready to be transferred into a larger container or media.
Once the plants show signs of sex, I can determine the next steps, whether that is culling plants with undesirable traits, preserving some for future breeding, or bringing stabilized genetics into production.
The whole breeding and seeding process is fascinating. In addition to being mentally stimulating and addicting, once you learn to enhance the genetic potential of your favorite cultivar, you will find it's easy to begin breeding many new cultivars. It's no different from breeding prize-winning horses at that point: Some win races and some do not. The fun comes from dreaming of what could be.
Kenneth Morrow is an author, consultant and owner of Trichome Technologies. Facebook: TrichomeTechnologies Instagram: Trichome Technologies Email: [email protected]
